Techniques for providing environmental lighting using network infrastructure

ABSTRACT

A network switch and luminaire provide environmental lighting via network infrastructure. The network switch operates in a communication mode that communicates, via a network interface, data with the luminaire over a network. Some portion of the data may be lighting control information for the luminaire that is produced by a control device. The network uses a network protocol that provides power to the luminaire using a network cable, where the luminaire uses the power to illuminate a lighting element. In response to a signal received by an emergency control input on the network switch, the emergency circuitry switches the network switch from the communication mode to an emergency lighting mode. The emergency lighting mode bypasses the processor used for communicating data via the network interface, and provides, via the network cable attached to the network interface, only power to the luminaire.

BACKGROUND

Though various options exist for providing general environmentallighting, few solutions exist that also ensure adequate illumination foregress during emergency situations. The requirements for such emergencylighting are specified by various standards, such as UL924 standardentitled “Standard for Safety of Emergency Lighting and PowerEquipment.” Emergency lighting equipment is intended to automaticallysupply illumination, electrical power, or both to critical areas andequipment in the event of failure of the normal supply, in accordancewith applicable standards, such as Article 700 or 701 of the NationalElectrical Code (National Fire Protection Association (NFPA) 70), theLife Safety Code (NFPA 101), the Fire Code (NFPA 1), the InternationalBuilding Code (IBC), and the International Fire Code (IFC).

In a configuration using network infrastructure to provide power toluminaires for environmental lighting, such as Power-over-Ethernet(PoE), the network switch provides the power to a luminaire based on anon-going negotiation with the luminaire via the network. Thus, in orderfor the network switch to provide power to the luminaire, the networkmust remain operational in order for the negotiation to occur.Maintaining the network relies, in part, upon a processor and firmwareexecuting in the network switch. However, certifying that networkdevices comply with emergency lighting standards, such as UL924, whensuch devices rely upon software components can be difficult. What isneeded are network devices that can provide emergency lighting, but thatdo not rely upon software-driven components to provide this capability.

SUMMARY

Various aspects of the present invention relate to a network switch andluminaire that provide environmental lighting via networkinfrastructure. The network switch operates in a communication mode thatcommunicates, via a network interface, data with the luminaire over anetwork. The network uses a network protocol that provides power to theluminaire using a network cable, and the luminaire uses the power toilluminate a lighting element. In response to a signal received by anemergency control input on the network switch, the emergency circuitryswitches the network switch from the communication mode to an emergencylighting mode. The emergency lighting mode of the network switchbypasses the processor used for communicating data via the networkinterface, and provides, via the network cable attached to the networkinterface, only power to the luminaire.

In response to link detection circuitry in the luminaire determiningthat no data has been received from the network switch for a thresholdtime period, the link detection circuitry then switches the luminairefrom communication mode to an emergency lighting mode. When in theemergency lighting mode, the link detection circuitry closes a relaythat bypasses the driver circuitry for the lighting elements of theluminaire, and provides power that is received from the networkinterface directly to the lighting elements that are configured foremergency lighting.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale, with emphasis instead being placed uponclearly illustrating the principles of the disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a drawing of a networked environment according to variousimplementations of the present disclosure.

FIG. 2 is a functional block diagram of a networked environmentaccording to various implementations of the present disclosure.

FIG. 3 is a flowchart illustrating one example of functionalityimplemented in a network switch in the networked environment of FIG. 1according to various implementations of the present disclosure.

FIG. 4 is a flowchart illustrating one example of functionalityimplemented in a luminaire in the networked environment of FIG. 1according to various implementations of the present disclosure

FIG. 5 is a schematic block diagram that provides one exampleillustration of a network switch employed in the networked environmentof FIG. 1 according to various implementations of the presentdisclosure.

FIG. 6 is a schematic block diagram that provides one exampleillustration of a luminaire employed in the networked environment ofFIG. 1 according to various implementations of the present disclosure.

DETAILED DESCRIPTION

Implementations of the present invention are generally directed tonetwork devices that provide environmental lighting, including emergencylighting that provides illumination for egress during emergencysituations. In various implementations, during normal operation (alsoreferred to as “communication mode”) a network switch communicates datawith the luminaire over a network using a network cable. The networkbetween the switch and the luminaire uses a network protocol, such asPower-over-Ethernet (PoE), that provides the luminaire with electricalpower for illuminating a lighting element using driver circuitry tocontrol the illumination.

When an emergency situation occurs, such as a fire alarm, the networkswitch receives an externally-generated signal indicating the emergencycondition. In response to receiving the signal, emergency circuitryswitches the network switch to an emergency lighting mode thatterminates the network protocol used to establish the network with theluminaire. With the network disabled, the network switch provides onlyelectrical power to the luminaire via the network cable. At theluminaire, a link detection relay detects that the network is no longerestablished, which causes the luminaire to switch into emergencylighting mode. Once the luminaire is in the emergency lighting mode, itcloses the link detection relay thereby providing power from the networkinterface directly to the lighting element used for emergency lighting.

With reference to FIG. 1, shown is an exemplary networked environment100 illustrating the environmental lighting functionality disclosedherein. The networked environment 100 includes an emergency signalgenerator 101, a network switch 103 and various luminaires 106 a . . .N. The luminaires 106 are in data communication with the network switch103 via corresponding network cables 109 a . . . N. The network cables109 can include unshielded twisted pair (UTP) cables, shielded twistedpair (STP) cables, and/or other types of cable suitable for carryingdata and electrical power, such as those defined by ANSI/TIA-568 and/orISO/IEC 11801. For example, the network cables 109 can include Category5 (Cat 5) specification cables as defined by ANSI/TIA-568.

The network switch 103 comprises a device with two or more networkinterfaces 112 a . . . N with which a network is established with eachof the one or more luminaires 106. The networks can be established usingany communication network protocol that provides the ability tonegotiate for and provide electrical power to network devices, such asthe luminaires 106. For example, the networks may implement a networkprotocol from the family of Ethernet standards that supportPower-over-Ethernet (PoE), such as IEEE 802.3af-2003, IEEE 802.3at-2009,and/or IEEE 802.3bt. Each of the luminaires 106 include one or morelighting elements, such as light-emitting diodes (LEDs) or fluorescentlamps, for providing environmental lighting in a room or other space.

The network switch 103 also includes an emergency control input withwhich it is communicatively coupled to the emergency signal generator101. The emergency signal generator 101 is a monitoring device capableof generating a notifying signal in the event that an emergencysituation (as may be defined) occurs in the facility where theluminaires 106 operate. For example, the emergency signal generator 101may be a Fire Alarm Control Panel (FACP) component of a fire alarmsystem, whereby the FACP generates a signal when the fire alarm systemfor the facility detects a fire. In some implementations, an emergencysignal is produced by a dry contact, Applied Transistor-Transistor Logic(TTL), a test switch, User Datagram Protocol (UDP) broadcast message,and/or other possible signaling techniques.

Next, a general description of the operation of the various componentsof the networked environment 100 is provided. To begin, the networkswitch 103 communicates with the luminaires 106 a-N to establish anetwork via each network interface 112 a-N. A feature of the networkprotocol used for each of the networks is the ability to provideelectrical power to devices in the network, in addition to supportingdata communications. Thus, while operating in this particularconfiguration with the network established (also referred to as“communications mode”), the network switch 103 is capable of providingpower to each of the luminaires 106 a-N as requested for illuminatingthe lighting elements. For example, using a PoE network protocol inconjunction with an application layer protocol, such as ANSI E1.31Streaming ACN (collectively referred to as “ANSI E1.31 sACN over PoE”),the network switch 103 (in the “power source equipment (PSE)” role)carries out an on-going negotiation with luminaires 106 a-N (in the“powered device (PD)” role) to determine the amount of power to supplyto the luminaires 106. In some implementations, the network switch 103may store a value for the amount of power negotiated for each luminaireand/or which network interfaces 112 are attached to devices requiringpower. In various implementations, manual electric switches (not shown),such as DIP switches, jumper blocks, etc., may be used in the networkswitch 103 to manually configure and store (i) a value for the amount ofpower to be provided on individual network interfaces 112 and/or (ii) anindicator for whether individual network interfaces 112 are eligible toprovide power. In further implementations, the network switch 103 alsoincludes analog power limiting circuitry (not shown), such as fuses,that limits the amount of power that may be consumed by individualand/or groups of network interfaces 112. The amount of power requestedby each luminaire 106 a-N for a given time interval may depend uponvarious power consumption factors, such as the amount of light outputneeded from the respective luminaire. The light output from theluminaires 106 a-N may depend upon one or more control devices, such asprogrammable lighting controllers, lighting consoles, dimmers, on/offswitches, programmed configurations, sensors, other luminaires, etc.associated with each luminaire, whereby the control data (also referredto as “lighting control information”) may be received directly by theluminaires 106 a-N and/or may be received by the luminaires 106 a-N viathe network switch 103. In some instances, a luminaire 106 may providelighting control information to other luminaires based on a controldevice associated with the luminaire 106 (e.g., an occupancy sensor forthe luminaire). In other instances, a luminaire 106 may receive lightingcontrol information originated from a second luminaire and forward thelighting control information to a third luminaire.

While operating in communication mode, the network switch 103 uses thenetwork protocol to communicate with and provide electrical power to theluminaires 106 a-N, which requires use of a processor in the networkswitch 103. When the emergency signal generator 101 detects an emergencysituation, it generates an emergency signal 115 that is transmitted tothe network switch 103. With reference to the exemplary functional blockdiagram shown in FIG. 2, the emergency signal is received by theemergency control input of the emergency circuitry 203 for the networkswitch 103. The emergency circuitry 203 is configured to perform theoperations necessary to switch the network switch from communicationsmode into emergency lighting mode in response to receiving an emergencysignal. To that end, the emergency circuitry 203 includes hardware logiccomponents that sense when an emergency signal is received and respondby bypassing the processor 206 used to implement the network protocolused for the network with each of the luminaires, such as with therepresentative luminaire 106 a. In the exemplary diagram of FIG. 2, thenetwork protocol is from the IEEE 802.3 family of standards for datacommunication and power distribution that is implemented over thenetwork cable 109 a, such as a Cat 5 cable. The processor 206 may bebypassed by various possible operations, such as by holding theprocessor 206 in a reset state using a reset switch 209, electricallyisolating the processor 206 from the network interfaces (not shown),such as the representative network interface 112 a, and/or otherpossible operations.

In addition to bypassing the processor 206, the emergency circuitry 203triggers a relay or other electrical switching component that appliespower from the power supply (not shown) directly to the networkinterface 112 a in order to transfer power to the luminaire 106 a. Thepower supply for the network switch 103 may be incorporated as a part ofthe network switch, be external to the network switch providing powervia a connected power cable, or other configurations as can beappreciated. For example, the power supply (either internal or external)may provide a 48 volt DC output that can be applied to the networkinterface 112 a. In some implementations, the amount of power suppliedto the individual network interfaces 112 during emergency lighting modeis preconfigured in the network switch 103. In other implementations,the amount of power supplied to the individual network interfaces 112during emergency lighting mode is based on a stored value negotiatedwith the corresponding luminaire 106 while the network switch 103 is incommunication mode. The negotiated value for the emergency lighting modemay be a value negotiated expressly for operating the luminaire 106 inemergency lighting mode, or the value used during the emergency lightingmode may be the most recent or highest value negotiated for operatingthe luminaire 106 in communication mode.

The network switch 103 applies power to specific pins of the networkinterface 112 a in order to transfer power through the conductors of thenetwork cable 109 a. For example, in the configuration shown in FIG. 2that uses PoE as a network protocol during communication mode, theelectrical power may be applied to pins of the network interface 112 adifferently depending upon the PoE implementation. In particular, PoEstandards (e.g., IEEE 802.3af/at/bt) specify an Alternative Aimplementation (shown) that applies positive voltage to data pins 1 and2, while the negative is applied to pins 3 and 6. The Alternative Bimplementation (not shown) instead applies positive voltage to pins 4and 5, and the negative to pins 7 and 8. Thus, when the emergencycircuitry 203 switches the network switch 103 to emergency lightingmode, the same pins of the network interface 112 a used to transferpower while in communications mode may still be used to transfer powerwhen in emergency lighting mode in which no network protocol is used.However, in other implementations (not shown), different pins may beused to transfer electrical power in emergency lighting mode than areused during communication mode.

For the luminaire 106 a that is connected to the network switch 103 viathe network cable 109 a, link detection circuitry 213 senses operationof the network protocol used to communicate with the network switch 103.While the network protocol used for the network is established with thenetwork switch 103, the luminaire 106 a is in communication mode. Whilein communication mode, the processor 216 manages the light output fromthe luminaire 106 a and also communicates with the network switch 103 asneeded, according to the network protocol, which may be used inconjunction with an application layer protocol (e.g., ANSI E1.31 sACNover PoE). The light output from the luminaire 106 a is produced by oneor more lighting elements 219, such as the LEDs shown in FIG. 2. Theprocessor 216 of the luminaire 106 a manages the light output via thedriver circuitry 222, such as the LED driver shown, that controls theLED lighting elements 219. The light output from the luminaire 106 a maydepend upon one or more control devices (not shown), such asprogrammable lighting controllers, lighting consoles, dimmers, on/offswitches, programmed configurations stored in memory, sensors, otherluminaires, etc. The control data for the control devices may bereceived via input directly to the luminaire 106 a (e.g., data from aphysical input) and/or may be received by the luminaire 106 a via thenetwork switch 103.

Based upon the activities of the luminaire 106 a, the processor 216 mayuse the network protocol to negotiate the amount of power to be suppliedby the network switch 103 to the luminaire 106 a via the network cable109 a and network interface 232. For example, if the network between theluminaire 106 a and the network switch 103 implements PoE using the IEEE802.3af network protocol, a preset maximum of 15.4 watts (W) may beprovided by the network switch, whereas IEEE 802.3at specifies a presetmaximum of 30 W that can be provided by the network switch (poweravailable to luminaires or other PDs may be less). Other standards,including those currently under development such as IEEE 802.3bt, mayalter these maximum power values. The amount of power requested by theluminaire 106 a for a given time interval (up to the maximum amount) maydepend upon various power consumption factors, such as the amount oflight output needed, the controls being used, and/or other powerconsumption activities of the luminaire 106 a.

In the event that an emergency situation occurs, an emergency signalcauses the network switch 103 to enter its emergency lighting mode that,among other activities, bypasses the processor 206 used to maintain thenetwork protocol with the luminaire 106 a. In implementations that usePoE as the network protocol, bypassing the processor 206 may terminatetransmission of Ethernet link pulses used as part of the physical layerauto-negotiation process of the network protocol. The loss of linkpulses is detectable by the luminaire 106 a and results in the loss ofthe “link” between the network switch 103 and the luminaire 106 a. Insome implementations, when an emergency signal is received, the networkswitch 103 also uses the network to send a message indicating theemergency situation to the luminaire 106 a prior to bypassing theprocessor 206.

Once the processor 206 of the network switch 103 is bypassed, the linkdetection circuitry 213 senses, via the network interface 232, that theprotocol used for the network with the network switch 103 is no longerin use (e.g., the link is lost). In implementations that use PoE as thenetwork protocol, the sensing may occur through circuitry that detectsEthernet link pulses used as part of the physical layer auto-negotiationprocess, whereby the link pulses can be used to detect the presence of aconnection to another Ethernet device, as can be appreciated. Forexample, the network may be declared disabled (i.e., the link is lost)if one or more link pulses have not been received for a threshold timeperiod specified by the network protocol. As a result of the loss of thenetwork protocol used for the network with the network switch 103,luminaire 106 a also enters emergency lighting mode. In someimplementations, the luminaire 106 may also enter the emergency lightingmode following receipt of a message, received from the network switch103 via the network, that indicates the emergency situation. Such anemergency message may be detected in the luminaire 106 a by the linkdetection circuitry 213 and/or by the processor 216 that may in turnsignal the link detection circuitry 213 to indicate that an emergencysituation exists.

In emergency lighting mode, the link detection circuitry 213 of theluminaire 106 a closes a relay or other similar electrical switchingcomponent that forms a closed circuit with the lighting elements 219 andspecific conductors of the network cable 109 a via the network interface232 (also referred to as a “bypass circuit”). Consequently, anyelectrical power provided by the network switch 103 to the network cable109 a will be applied to power the lighting elements 219 in theemergency lighting mode (also referred to as the “emergency lightingelements”). In some implementations, the lighting elements used duringemergency lighting mode may be the same as or different from thelighting elements used during communication mode, which may affect thepower needs of the luminaire 106 a when operating in the differentmodes. In various implementations, the bypass circuit created by thelink detection circuitry 213 also bypasses the driver circuitry 222 andpossibly the processor 216, such as shown in FIG. 2. Thereafter, theluminaire 106 a may continue to provide emergency lighting using theelectrical power received from the network switch 103, at least whilethe communication network is non-functional.

Referring next to FIG. 3, shown is a flowchart that provides one exampleof the operation of a portion of the network switch 103 that isconfigured to provide environmental lighting, including lighting foremergency situations. It is understood that the flowchart of FIG. 3provides merely an example of the many different types of functionalarrangements that may be employed to implement the operation of thenetwork switch 103 as described herein. As an alternative, the flowchartof FIG. 3 may be viewed as depicting an example of elements of a methodimplemented in the network switch 103 according to one or moreimplementations.

The operations depicted in the flowchart of FIG. 3 may be initiated oncethe network switch 103 is connected to a luminaire 106 (FIG. 1) via anetwork cable 109 (FIG. 1). Beginning with block 303, the network switch103 communicates with a luminaire 106 to establish a network, whereby afeature of the network protocol used for the network is the ability toprovide electrical power to devices in the network, in addition tosupporting data communications. For example, the network may be anEthernet network that includes PoE from the IEEE 802.3 family ofstandards, but other types of networks offering both data communicationand electrical power for devices are possible.

Next, in block 306, the network switch 103 communicates with andprovides power to the luminaire 106 using the network established viathe network cable. Thus, while operating in this particularconfiguration with the network established (i.e., “communication mode”),the network switch 103 provides the amount of power to the luminaire 106that is requested, presuming the requested power is within limitsspecified by the network protocol and within the capability of thenetwork switch 103. For example, using a PoE network protocol, thenetwork switch 103 (in the PSE role) carries out an on-going negotiationwith luminaire 106 (in the PD role) to determine the amount of power tosupply to the luminaire 106. The amount of power requested by eachluminaire 106 a-N for a given time interval may depend upon variouspower consumption factors, such as the amount of light output neededfrom the respective luminaire. The network switches 103 uses itsprocessor to carry out communication with the luminaire 106 using thenetwork protocol, including the negotiation of power to be supplied viathe network cable 109.

Then, in block 309, the network switch 103 uses its emergency circuitryto detect if an emergency signal has been received via its emergencycontrol input. If no emergency signal is detected, the network switchremains in communication mode and returns to block 306. Alternatively,if an emergency signal was detected by the emergency circuitry, theemergency circuitry of the network switch 103 is configured to performthe operations necessary to switch the network switch fromcommunications mode into emergency lighting mode, as described startingin block 312.

In block 312, the emergency circuitry of the network switch 103 bypassesthe processor of the network switch that is used to implement thenetwork protocol for the network with the luminaire 106. The processormay be bypassed by various possible operations, such as by holding theprocessor in a reset state using a reset switch, electrically isolatingthe processor from the network interfaces, and/or other possibleoperations.

Subsequently, in block 315, the emergency circuitry of the networkswitch 103 also triggers a relay or other electrical switching componentthat applies power from its power supply directly to specific pins ofthe network interface 112 (FIG. 1) in order to transfer power throughthe conductors of the network cable 109. As described above, when theemergency circuitry switches the network switch 103 to emergencylighting mode, the same pins of the network interface 112 used totransfer power while in communications mode may still be used totransfer power when in emergency lighting mode in which no networkprotocol is used (i.e., the network is disabled). However, in otherimplementations, different pins may be used to transfer electrical powerin emergency lighting mode than are used during communication mode.

Next, in block 318, the network switch 103 determines if communicationmode should be restored. Communication mode may be restored in the eventthat the emergency situation is resolved and the emergency signal thattriggered the emergency mode is cleared. The emergency signal may becleared by discontinuing the emergency signal for a time period,receiving a different signal indicating the emergency situation isresolved, or by another operation as may be defined for the particulartype of emergency input. In the event that the emergency signal is notcleared, the network switch returns to block 315.

In the event that the emergency signal is cleared, the network switch103 may return to block 303 and return to communication mode. Intransitioning back to communication mode, the relay of the emergencycircuitry opens to terminate the power being applied directly to thenetwork interface 112 from the power supply, and the processor of thenetwork switch 103 again manages the network protocol to communicatewith and provide electrical power, if so configured, to the luminaire106.

Referring next to FIG. 4, shown is a flowchart that provides one exampleof the operation of a portion of a luminaire 106 that is configured toprovide environmental lighting, including lighting for emergencysituations. It is understood that the flowchart of FIG. 4 providesmerely an example of the many different types of functional arrangementsthat may be employed to implement the operation of the luminaire 106 asdescribed herein. As an alternative, the flowchart of FIG. 4 may beviewed as depicting an example of elements of a method implemented inthe luminaire 106 according to one or more implementations.

The operations depicted in the flowchart of FIG. 4 may be initiated oncethe luminaire 106 is connected to a network switch 103 (FIG. 1) via anetwork cable 109 (FIG. 1). Beginning with block 403, the luminaire 106communicates with the network switch 103 to establish a network, wherebya feature of the network protocol used for the network is the ability toprovide electrical power to devices in the network, in addition tosupporting data communications. For example, the network may be anEthernet network that includes PoE from the IEEE 802.3 family ofstandards using data communications, such as ANSI E1.31 sACN, at theapplication layer (collectively referred to as “ANSI E1.31 sACN overPoE”), but other types of networks offering both data communication andelectrical power for devices are possible. Link detection circuitry inthe luminaire 106 senses operation of the network protocol used tocommunicate with the network switch 103. In some implementations, theoperation of the network is sensed at the physical layer (i.e., Layer 1of the OSI model) by detecting link pulses, the absence of which mayindicate that the network is disabled (the “link” is lost). While thenetwork protocol used for the network is established with the networkswitch 103, the luminaire 106 is in communication mode.

While in communication mode, in block 406, the processor of theluminaire 106 manages the light output from the luminaire and alsocommunicates with the network switch 103 as needed (e.g., using ANSIE1.31 sACN over PoE). In some implementations, the luminaire 106 mayfurther receive control information from a control device via thenetwork switch 103. The light output from the luminaire 106 is producedby one or more lighting elements, such as LEDs. The processor of theluminaire 106 manages the light output via driver circuitry, such as anLED driver that controls the LED lighting elements. Based upon theactivities of the luminaire 106, the processor uses the network protocolto negotiate the amount of power to be supplied by the network switch103 to the luminaire 106 via the network cable 109. The amount of powerrequested by the luminaire 106 for a given time interval (up to themaximum amount) may depend upon various power consumption factors, suchas the amount of light output needed, the controls being used, and/orother power consumption activities of the luminaire 106.

In block 409, the link detection circuitry of the luminaire 106determines, via the network interface 232 (FIG. 2) for the luminaire, ifthe protocol used for the network with the network switch 103 is nolonger in use (i.e., the network is lost or disabled). Inimplementations that use the IEEE 802.3 family of standards for thenetwork, the determination may occur through circuitry that detectsEthernet link pulses used as part of the physical layer auto-negotiationprocess, whereby the link pulses can be used to detect the presence of aconnection to another Ethernet device, as can be appreciated. Forexample, the network may be declared disabled if one or more link pulseshave not been received for a threshold time period specified by thenetwork protocol. If the link detection circuitry of the luminaire 106detects that the network protocol, such as the protocol for the physicallayer (Layer 1), is still in use (i.e., the network is not lost), theluminaire returns to block 406. Alternatively, if the link detectioncircuitry of the luminaire 106 detects that the network protocol, suchas for the physical layer protocol, is no longer in use on the networkinterface 232 (i.e., the network has been lost or disabled), theluminaire 106 proceeds to block 412 and enters emergency lighting mode.

In block 412, the link detection circuitry 213 of the luminaire 106 abypasses the driver circuitry of the luminaire 106 by closing a relay orother similar electrical switching component that forms a bypass circuitwith the lighting elements and specific conductors of the network cable109 via the network interface 232.

Consequently, in block 415, the electrical power provided by the networkswitch 103 to the network cable 109 will be applied to power thelighting elements in the emergency lighting mode, while the network isdisabled. In some implementations, the lighting elements used duringemergency lighting mode may be the same as or different from thelighting elements used during communication mode.

Next, in block 418, the link detection circuitry of the luminaire 106determines, via the network interface 232 for the luminaire, if theprotocol used for the network with the network switch 103 has beenrestored. If the link detection circuitry of the luminaire 106determines that the network protocol is not present on the networkinterface 232, the luminaire 106 returns to block 415 where it maycontinue to provide emergency lighting using the electrical powerreceived from the network switch 103 while the communication network isnon-functional. Alternatively, if the link detection circuitrydetermines that the network protocol has been restored to the networkinterface 232 (i.e., an indication that the emergency situation hascleared), the luminaire returns to block 403 and transitions fromemergency mode back to communication mode. As part of the transition,the link detection circuitry again opens the relay that created theclosed circuit between the lighting elements and the conductors of thenetwork cable 109 via the network interface 232.

Next, in FIG. 5, shown is a block diagram depicting an example of anetwork switch 103 used for implementing the techniques disclosed hereinwithin a networked environment 100. The network switch 103 can include aprocessing device 206. Non-limiting examples of the processing device206 include a microprocessor, an application-specific integrated circuit(“ASIC”), a state machine, or other suitable processing device. Theprocessing device 206 can include any number of processing devices,including one. The processing device 206 can be communicatively coupledto computer-readable media, such as memory device 504. The processingdevice 206 can execute computer-executable program instructions and/oraccess information respectively stored in the memory device 504.

The memory device 504 can store data and instructions that, whenexecuted by the processing device 206, cause the processing device 206to perform some or all of the operations described herein. For example,the memory device 504 may include a management application 521comprising instructions and data that cause the network switch 103 toperform communication mode functionality. The memory device 504 may be anon-transitory computer-readable medium, such as (but not limited to) anelectronic, optical, magnetic, or other storage device capable ofproviding a processor with computer-readable instructions. Non-limitingexamples of such optical, magnetic, or other storage devices includeread-only (“ROM”) device(s), random-access memory (“RAM”) device(s),magnetic disk(s), magnetic tape(s) or other magnetic storage, memorychip(s), an ASIC, configured processor(s), optical storage device(s), orany other medium from which a computer processor can read instructions.The instructions may comprise processor-specific instructions generatedby a compiler and/or an interpreter from code written in any suitablecomputer-programming language. Non-limiting examples of suitablecomputer-programming languages include C, C++, C#, Visual Basic, Java,Python, Perl, JavaScript, and the like.

The network switch 103 can include a bus 506 that can communicativelycouple one or more components of the corresponding device. Although theprocessor 206, the memory 504, and the bus 506 are depicted in FIG. 5 asseparate components in communication with one another, otherimplementations are possible. For example, the processor 206, the memory504, and the bus 506 can be components of printed circuit boards orother suitable devices that can be disposed in a network switch 103 tostore and execute programming code.

The network switch 103 also includes network interfaces 112 andemergency circuitry 203. The network interfaces 112 can includetransceiving devices configured for communication using one or morenetwork protocols capable of providing data communication and electricpower distribution. As a non-limiting example, the network interfaces112 can include 1000BASE-T interfaces that comply with the IEEE 802.3atstandard. The emergency circuitry 203 includes hardware logic componentsthat sense when an emergency signal is received and respond by (i)bypassing the processor 206 and (ii) engaging a relay or otherelectrical switching component that applies power from a power supplydirectly to specific pins of the network interfaces 112.

In FIG. 6, shown is a block diagram depicting an example of a luminaire106 used for implementing the techniques disclosed herein within anetworked environment 100. The luminaire 106 can include a processingdevice 216. Non-limiting examples of the processing device 216 include amicroprocessor, an ASIC, a state machine, or other suitable processingdevice. The processing device 216 can include any number of processingdevices, including one. The processing device 216 can be communicativelycoupled to computer-readable media, such as memory device 604. Theprocessing device 216 can execute computer-executable programinstructions and/or access information respectively stored in the memorydevice 604.

The memory device 604 can store data and instructions that, whenexecuted by the processing device 216, cause the processing device 216to perform some or all of the operations described herein. For example,the memory device 604 may include a management application 621comprising instructions and data that cause the luminaire 106 to performcommunication mode functionality. The memory device 604 may be anon-transitory computer-readable medium, such as (but not limited to) anelectronic, optical, magnetic, or other storage device capable ofproviding a processor with computer-readable instructions. Non-limitingexamples of such optical, magnetic, or other storage devices includeread-only (“ROM”) device(s), random-access memory (“RAM”) device(s),magnetic disk(s), magnetic tape(s) or other magnetic storage, memorychip(s), an ASIC, configured processor(s), optical storage device(s), orany other medium from which a computer processor can read instructions.The instructions may comprise processor-specific instructions generatedby a compiler and/or an interpreter from code written in any suitablecomputer-programming language. Non-limiting examples of suitablecomputer-programming languages include C, C++, C#, Visual Basic, Java,Python, Perl, JavaScript, and the like.

The luminaire 106 can include a bus 606 that can communicatively coupleone or more components of the corresponding device. Although theprocessor 216, the memory 604, and the bus 606 are depicted in FIG. 6 asseparate components in communication with one another, otherimplementations are possible. For example, the processor 216, the memory604, and the bus 606 can be components of printed circuit boards orother suitable devices that can be disposed in a luminaire 106 to storeand execute programming code.

The luminaire 106 also includes one or more network interfaces 232 andlink detection circuitry 213. The network interface(s) 232 can includeone or more transceiving devices configured for communication using oneor more network protocols capable of providing data communication andelectric power distribution. As a non-limiting example, the networkinterface(s) 232 can include one or more 1000BASE-T interfaces thatcomply with the IEEE 802.3at standard. The link detection circuitry 213includes hardware logic components that sense when the network protocolon the network interface 232 has become non-functional (i.e., thenetwork link is lost) and respond by closing a relay or other similarelectrical switching component in order to form a bypass circuit withthe lighting elements of the luminaire and specific pins of the networkinterface 232.

Numerous specific details are set forth herein to provide a thoroughunderstanding of the claimed subject matter. However, those skilled inthe art will understand that the claimed subject matter may be practicedwithout these specific details. In other instances, methods,apparatuses, or systems that would be known by one of ordinary skillhave not been described in detail so as not to obscure claimed subjectmatter.

Some portions are presented in terms of algorithms or symbolicrepresentations of operations on data bits or binary digital signalsstored within a computing system memory, such as a computer memory.These algorithmic descriptions or representations are examples oftechniques used by those of ordinary skill in the data processing artsto convey the substance of their work to others skilled in the art. Analgorithm is a self-consistent sequence of operations or similarprocessing leading to a desired result. In this context, operations orprocessing involves physical manipulation of physical quantities.Typically, although not necessarily, such quantities may take the formof electrical or magnetic signals capable of being stored, transferred,combined, compared or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to such signalsas bits, data, values, elements, symbols, characters, terms, numbers,numerals, or the like. It should be understood, however, that all ofthese and similar terms are to be associated with appropriate physicalquantities and are merely convenient labels. Unless specifically statedotherwise, it is appreciated that throughout this specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating,” “determining,” and “identifying” or the like refer toactions or processes of a computing device, such as a network device ora similar electronic computing device or devices, that manipulate ortransform data represented as physical electronic or magnetic quantitieswithin memories, registers, or other storage devices, transmissiondevices, or display devices of the computing platform.

The system or systems discussed herein are not limited to any particularhardware architecture or configuration. A computing device, such as thenetwork switch 103 or luminaire 106, can include any suitablearrangement of components that provide a result conditioned on one ormore function calls. Suitable computing devices include multipurposemicroprocessor-based computer systems accessing stored software thatprograms or configures the computing system from a general-purposecomputing apparatus to a specialized computing apparatus implementingone or more aspects of the present subject matter. Any suitableprogramming, scripting, or other type of language or combinations oflanguages may be used to implement the teachings contained herein insoftware to be used in programming or configuring a computing device.

Aspects of the methods disclosed herein may be performed in theoperation of such computing devices. The order of the blocks presentedin the examples above can be varied—for example, blocks can bere-ordered, combined, and/or broken into sub-blocks. Certain blocks orprocesses can be performed in parallel.

The use of “adapted to” or “configured to” herein is meant as open andinclusive language that does not foreclose devices adapted to orconfigured to perform additional tasks or steps. Additionally, the useof “based on” is meant to be open and inclusive, in that a process,step, calculation, or other action “based on” one or more recitedconditions or values may, in practice, be based on additional conditionsor values beyond those recited. Headings, lists, and numbering includedherein are for ease of explanation only and are not meant to belimiting.

While the present subject matter has been described in detail withrespect to specific aspects thereof, it will be appreciated that thoseskilled in the art, upon attaining an understanding of the foregoing,may readily produce alterations to, variations of, and equivalents tosuch aspects. Accordingly, it should be understood that the presentdisclosure has been presented for purposes of example rather thanlimitation, and does not preclude inclusion of such modifications,variations, and/or additions to the present subject matter as would bereadily apparent to one of ordinary skill in the art.

Therefore, the following is claimed:
 1. A luminaire, comprising: aprocessor; a network interface; one or more lighting elements; drivercircuitry for controlling the one or more lighting elements; linkdetection circuitry; a memory configured by a management applicationexecuted by the processor of the luminaire, the management applicationcausing the luminaire to: operate in a communication mode comprising:communicating, via the network interface, data with a network switchover a network, wherein the network uses a network protocol thatprovides power to the luminaire using a network cable; and managing thedriver circuitry to control illumination of the one or more lightingelements; and in response to the link detection circuitry determiningthat no data has been received from the network switch for a thresholdtime period, the link detection circuitry switches the luminaire fromsaid communication mode to an emergency lighting mode causing theluminaire to: operate in the emergency lighting mode comprising:providing power that is received from the network interface directly tothe one or more lighting elements while the power bypasses the drivercircuitry.
 2. The luminaire of claim 1, wherein the one or more lightingelements are one or more Light-Emitting Diodes (LEDs), and the drivercircuitry is an LED driver.
 3. The luminaire of claim 1, whereincommunicating data with the network switch further comprises negotiatingan amount of power needed by the luminaire.
 4. The luminaire of claim 3,wherein negotiating the amount of power is conducted using the networkprotocol that is defined by the IEEE 802.3 family of standards.
 5. Theluminaire of claim 4, wherein the link detection circuitry determiningthat no data has been received from the network switch for the thresholdtime period comprises determining that link pulses have not beenreceived according to the network protocol.
 6. The luminaire of claim 1,wherein the network cable conforms at least to the Category 5 (Cat 5)specification defined by ANSI/TIA-568.
 7. The luminaire of claim 1,further comprising: while in the emergency lighting mode, in response tothe link detection circuitry determining that data is being receivedfrom the network switch via the network interface, switching theluminaire from the emergency lighting mode to the communication mode,wherein the communication mode restores power to the driver circuitryfor controlling the one or more lighting elements.
 8. A method for aluminaire to provide lighting via network infrastructure, comprising:operating the luminaire in a communication mode comprising:communicating, via a network interface, data with a network switch overa network, wherein the network uses a network protocol that providespower to the luminaire using a network cable; and managing drivercircuitry that controls illumination of one or more lighting elements;and in response to link detection circuitry determining that no data hasbeen received from the network switch for a threshold time period, thelink detection circuitry switches the luminaire from operating in thecommunication mode to operating in an emergency lighting mode; andoperating the luminaire in the emergency lighting mode comprising:bypassing the driver circuitry that controls the illumination of the oneor more lighting elements; and providing power that is received from thenetwork interface directly to the one or more lighting elements that areconfigured for emergency lighting.
 9. The method of claim 8, wherein theone or more lighting elements are one or more Light-Emitting Diodes(LEDs), and the driver circuitry is an LED driver, and wherein operatingthe luminaire in the communication mode comprises powering a firstplurality of LEDs and operating the luminaire in the emergency lightingmode comprises powering a second plurality of LEDs, wherein the secondplurality of LEDs is more than the first plurality of LEDs.
 10. Themethod of claim 8, wherein communicating data with the network switchfurther comprises negotiating an amount of power needed by the luminaireaccording to the IEEE 802.3 family of standards.
 11. The method of claim10, wherein the link detection circuitry determining that no data hasbeen received from the network switch for the threshold time periodcomprises determining that link pulses have not been received accordingto the network protocol.
 12. The method of claim 10, wherein a maximumamount of power negotiated depends upon the network protocol and isselected from a plurality of possible presets comprising a maximum of:15.4 Watts (W) and 30 W.
 13. The method of claim 8, wherein operatingthe luminaire in the emergency lighting mode further comprises bypassinga processor used by the luminaire during the communication mode.
 14. Themethod of claim 8, wherein a first set of inputs on the networkinterface provide power during the communication mode and a second setof inputs provide power during the emergency lighting mode, and whereinproviding power that is received from the network interface directly tothe one or more lighting elements, comprises connecting the second setof inputs to the one or more lighting elements.
 15. The method of claim8, while in the emergency lighting mode, in response to the linkdetection circuitry determining that data is being received from thenetwork switch, switching the luminaire from operating in the emergencylighting mode to operating in the communication mode, wherein operatingthe luminaire in the communication mode comprises using the drivercircuitry to control illumination of the one or more lighting elements.16. A luminaire, comprising: a processor; a network interface; one ormore lighting elements; driver circuitry for the one or more lightingelements; link detection circuitry; a memory configured by a managementapplication executed by the processor of the luminaire, the managementapplication causing the luminaire to: operate in a communication modecomprising: communicating, via the network interface, data with anetwork switch over a network, wherein the network uses a networkprotocol that provides power to the luminaire using a network cable, thedata including lighting control information produced for the luminaireby a control device; and managing the driver circuitry that controlsillumination of the one or more lighting elements; and in response toreceiving a message from the network switch that indicates an emergencysituation, the link detection circuitry switches the luminaire from saidcommunication mode to an emergency lighting mode causing the luminaireto: operate in the emergency lighting mode comprising: bypassing thedriver circuitry that controls the illumination of the one or morelighting elements; and providing power that is received from the networkinterface directly to the one or more lighting elements that areconfigured for emergency lighting.
 17. The luminaire of claim 16,wherein the one or more lighting elements are one or more Light-EmittingDiodes (LEDs), and the driver circuitry is an LED driver.
 18. Theluminaire of claim 16, wherein communicating data with the networkswitch further comprises negotiating an amount of power needed by theluminaire.
 19. The luminaire of claim 16, wherein the control devicecommunicates with the luminaire via the network switch to controlillumination of the one or more lighting elements, wherein the controldevice is a programmable lighting controller, a lighting console, adimmer, a switch, a sensor, or other luminaire.
 20. The luminaire ofclaim 16, wherein the link detection circuitry is also configured toswitch the luminaire to the emergency lighting mode when no data hasbeen received from the network switch for a threshold time period.